Process of manufacturing plywood



s. B. HENNING.

PROCESS OF MANUFACTURING PLYWOOD.

# ARPL'ICATION FILED JUNE 19, 1918.

Patented Feb. 3, 1920.

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T0 THEHUNITEID STATES PROCESS OF MANUFACTURING PLYWOOD/ Specification of Letters-Patent.

Application filed June19, 1918. Serial No. 240,842.

To all whom it may concern:

lie it known that I, SIIERBURNE B. HEN- xrxo. a citizen of United States, residing at Madison, in the county of Dane and State of \Visconsin. haveinvented a new and useful Improvement in Processes of Manufacturing Plywood, of which the following is a specification. 1

.Hy invention relates to the manufacture of waterproof plywood and consists in co n-- bining certain materials 111 definite proportion and then in using in a particular manner the composition prepared.

The object of my invention is the production of a waterproof plywood. Plywood made in accordance with my invention is especially adapted for use as a covering for a surface which is subjected to extreme changes in moisture conditions. be used where a material is required which must be light and strong and will not be affected by moisture.

In the accompanying drawing:

Figure 1 illustrates three plies of material to which glue may be applied;

Fig. 2 shows three plies of material in a press in which heat is'not used;

Fig. 3 shows three plies of material in a press in which heat is applied in the usual way. 7

In carrying out my invention I prepare the glue of the following ingredients using approximately the following proportions of said ingredients: one hundred (100) parts by Weight of powdered casein, four hundred (400) to six hundred (600) parts of water, fifteen (15) to eight (8) parts water slaked lime, and ten (10) to thirty- (30) parts of dry granulated blood albumin (black soluble). The albumin should be of pass through a ten (10) mesh sieve.

The casein is soaked one hour ini all the water. The dry powdered lime is tlien added, and the mixture is stirred for about ten minutes. The granulated dry blood albumin is then added to the mixture by stirring. minutes, it is ready for use.

It will be noted that the proportion of limeused varies inversely to the proportion of water and blood albumin used.

In manufacturing plywood this glue is spread on the plies in any of the usual ways. The plies are then cold pressed for about It may also After this mixture has stood for 15' Patented Penis, 1920.

one-half hour, the pressure maintained be ing between fifty (50) and one hundred (100) pounds per square inch. The plies are then subjected to approximately the same pressure in ahot press, the temperatureof which is approximately 212 Fah renheit. Thin plies are kept in the hot pressfor about two minutes while a longer period is required for thicker plies.

.W'hat I claim is:

1. The process of manufacturing plywood which comprises assembling a plurality of plies of fibrous material with a caseinblood adhesive between the adjacent faces thereof, subjecting the same to a relatively high cold pressure for a shoit period, and thereafter subjecting the same to a substantially equal hot pressure fora shorter period.

2. The process of manufacturing plywood, which comprises assembling a plurality of plies of fibrous material with acasein glue between the adjacent faces thereof, subjecting the same to a relatively high cold pressure for a short period and thereafter subjecting the san'ie to a substantially equal hot pressure for a shorter period.

3. The process of manufacturing plywood, which comprises assembling a plurality of plies of fibrous material with a casein-blood adhesive material between the adjacent faces thereof, subjecting the same to a cold pressure of from fifty to one hundred pounds for approximately a half hour, and thereafter subjecting the same to a substantially equal. hot pressure for a shorter period.

4. The process of manufacturing plywood, which comprises assembling a plurality of plies of fibrous material with a casein glue between the adjacent faces thereof, subjecting the same to a cold pressure of from fifty to one hundred pounds for approximately a half hour, and then subjecting the same to a substantially equal hot pressure for a shorter period.

5. The process of manufacturing plywood, which comprises assembling a plurality of plies of fibrous material with an adhesive consisting of casein, water, lime, and albumin, between the adjacent faces thereof, subjecting the same to a relatively high cold pressure for a short period. and thereafter subjecting the same to a substantially equal hot pressure for a shorter period.

6. The process of manufacturing plywood,

which comprises assembling (r plurality of plies of fibrous material with an adhesive comprislng approximately: 100 parts by' weight of powdered casein, 400 to 600 parts 5 of Water, 15 E08 parts of water slaked lime,-

and 10 to 30 parts of blood albumin plececl between the adjacent faces thereof, Sllb]6Ct ing the same to u relutirely high cold pressure for :1 short period, and thereafter subjecting the same to 21 substantially equal hot. pressure for a shorter period.

In testimony whereof I have hereunto affixed my signature.

SHERBUR'NE B. HENNING. 

